I am not the best person to ask about Sennheiser as I don't like them, they are far from neutral and have a llot of sibilance which is unacceptable for audio editing.
Comfort wise, you can not beat the ATH-AD700s or AD900s, but the sound may be too different from the Sennheiser for you. They are much more neutral with a distinct de-emphasis of the low end, although the only open cans that have truly great bass are my Grado PS1000s/GS1000s in my opinion.

I wish I could help more, but I just don't like the Sennheiser sound so I don't know how to recommend anything similar...

I am not the best person to ask about Sennheiser as I don't like them, they are far from neutral and have a llot of sibilance which is unacceptable for audio editing.
Comfort wise, you can not beat the ATH-AD700s or AD900s, but the sound may be too different from the Sennheiser for you. They are much more neutral with a distinct de-emphasis of the low end, although the only open cans that have truly great bass are my Grado PS1000s/GS1000s in my opinion.

I wish I could help more, but I just don't like the Sennheiser sound so I don't know how to recommend anything similar...

I don't care about the sound at this point, I just need something that is as comfortable as the HD 598, they are the only headphones that have never pushed my glasses frames up against my head.

The AD 700's are ok, but they are to big for my head, I am walys readjusting them and they slide down my head...